If you’re looking to get the most out of every ride—whether that’s holding speed on the flat or spinning comfortably up steep climbs—the Shimano Ultegra R8101 12-speed cassette gives you the range and refinement to do both.

With a choice of 11–30T or 11–34T ratios, you can tune your gearing to suit your riding style. The 11–30T option offers tighter steps between gears, helping you maintain a smooth, consistent cadence when riding fast or on rolling terrain. Switch to the 11–34T and you’ll gain easier climbing gears that take the pressure off on longer or steeper gradients, ideal for endurance rides or mixed routes.

On the road, everything feels seamless. With 12 speeds, the jumps between gears are small and natural, so you can fine-tune your effort without losing rhythm. Shifts are quick, smooth and dependable, even when you're pushing hard on a climb or accelerating out of the saddle.

A lightweight carrier keeps the overall weight down, while durable sprockets ensure long-lasting performance through regular riding in all conditions. It’s designed to work perfectly with Shimano’s latest 12-speed drivetrains, giving you a setup that feels quiet, efficient and easy to live with.

• Choice of ratios (11–30T or 11–34T) – tailor gearing for speed or climbing
• 12-speed performance – smooth, closely spaced gear steps
• Fast, reliable shifting – consistent gear changes under load
• Optimised cadence control – helps maintain rhythm across varied terrain
• Lightweight carrier design – reduces weight without sacrificing strength
• Durable sprockets – built for long-lasting everyday performance
• Seamless Shimano 12-speed compatibility Ideal for road, endurance and mixed-terrain riding

• Model: CS-R8101
• Series: Shimano Ultegra
• Speeds: 12-speed
• Available Ratios:

• 11–30T (tighter gearing for fast, smooth riding)
• 11–34T (wide range for easier climbing and endurance rides)

Sprocket Material: Steel (with lightweight alloy carriers) Carrier: Aluminium spider Shifting Technology: Shimano Hyperglide Freehub Compatibility: Shimano/SRAM HG freehub (11-speed road compatible) Recommended Chain: Shimano 12-speed chain Weight: Approx. 290–360 g (varies by ratio)